Multiple, anatomically distinct lung cancer tumors may frequently arise from a single cancer cell, according to a retrospective analysis of patient tumor samples published in the April 7 online issue of the Journal of the National Cancer Institute.
Some lung cancer patients have multiple anatomically distinct tumors at the time of diagnosis. Although such multiple tumors usually share a common appearance, it has been unclear whether they arise from a single tumor or are independent primary cancers.
In the current study, Liang Cheng, M.D., of the Indiana University School of Medicine in Indianapolis, and colleagues examined 70 lung cancer tumors from 23 female and seven male patients to determine whether multiple tumors from an individual patient shared a common genetic pattern. The investigators analyzed the tumors for chromosome loss at six loci previously associated with lung cancer and for mutations in the TP53 gene. They also analyzed the X-chromosome inactivation pattern in tumors from female patients.
Based on these three analyses, the investigators concluded that the multiple tumors in 23 of the 30 patients (77 percent) arose from a single cancer clone.
"Our findings support the current classification of multifocal lung cancers as advanced-stage cancers…rather than separate primary cancers and the use of therapeutic strategies tailored for patients with advanced-staged cancers," the authors write.